This proposal outlines a development program to transition a second generation Transdermal Tuberculosis (TB) Skin Test into a commercial product. The first generation of the technology, transdermal delivery of a protein of the M. tuberculosis complex (MPB/T-64) by a Torii patch, has already been tested in three clinical trials performed in the Philippines and Japan: it demonstrated remarkable ability to specifically identify active cases of TB (smear positive TB patients), while it was non-reactive in symptom-free individuals PPD positive from either BCG vaccination or prior cure of TB. Sequella licensed this exciting technology from the Japan BCG Laboratory, and GMP manufacturing of recombinant MPT64 began in January 2003. We will begin a World Health Organization-supported clinical trial in South Africa in March 2003 that will test the sensitivity and specificity of this first generation test. We believe that the Transdermal TB Skin Test will be an invaluable tool in the fight against TB. Because of the incredible need for a rapid diagnostic for active TB, we hope to begin distribution in the developing world as soon as possible using the existing test format. However, there are many aspects of the product that need to be improved, and we hope to develop a more effective second generation product in this proposal. Our specific aims include: Specific Aim I: We will optimize expression, purification, and quality control protocols for MPT64. Specific Aim II: We will complete development of a second-generation patch technology that incorporates the protein directly into the patch adhesive. Specific Aim III: We will manufacture the second-generation patches for clinical studies using Good Manufacturing Practices. Specific Aim IV: We will perform clinical studies of the Transdermal TB Skin Test.